Before Subway Attack Charges, Frank James Had Decades of Petty Offenses

“He wasn’t making direct threats,” he said. “James is an intelligent person. But he was making very angry comments, with lots of expletives. Scary stuff.”

“We called the Elizabeth police because some of our people were really scared,” Mr. Storch said.

Mr. James appeared to resent mental health treatment: In several of the videos he posted to YouTube, he assailed the workers whom he said had treated him at a different organization, the South Bronx Mental Health Council, with racist insults.

Later, in 2007, Mr. James was convicted of disorderly conduct in Hoboken, N.J., and, in 2011, he was taken to court in Philadelphia over unpaid credit card debt. Details on the 2007 case in Hoboken were not immediately available from court documents.

After that, there was a period of relative silence. Though public records indicate that Mr. James spent time in Chicago, he does not appear to have been arrested there. Neither was he taken into custody in Milwaukee, where he lived in a rooming house on the city’s South Side.

It was a rough place. David Lorenz, who was a resident at the same time as Mr. James, said that it was a haven for people who were down on their luck, and “trying to keep their nose clean.” Mr. Lorenz said it was not unusual for the home to rent apartments to people who were recently released from prison or suffering from drug addiction or mental health problems.

According to his videos and public records, Mr. James lived in Milwaukee until March. After moving out of the rooming house, he rented an apartment nearby, where he again had trouble with his neighbors. Keilah Miller, who lived next to Mr. James, called him a “really weird neighbor” and said that he had confronted her aggressively after she mistakenly left her key in the lock.

Ms. Miller said Tuesday that she had not seen Mr. James since late March. By then, according to the authorities and to Mr. James’s own posts on social media, he was already on his way back east, where, as he put it in one video, “all my troubles started.”

Téa Kvetenadze, Michael LaForgia and Dan Simmons contributed reporting.